Synthesis and photophysical properties of europium pentafluorinated -diketonate complexes

摘要

Two pentafluorinated -diketone ligands, 4,4,5,5,5-pentafluoro-1-(4-methoxyphenyl)pentane-1,3-dione (PFMP) and 4,4,5,5,5-pentafluoro-1-(4-dimethyl amino-phenyl)pentane-1,3-dione (PFAP), had been employed to synthesize six novel europium (III) complexes with ancillary ligands 2,2-dipyridine, 1,10-phenanthroline and 4,7-diphenyl-1,10-phenanthroline. The synthesized europium (III) complexes were characterized by FTIR, H-1 NMR, UV-Vis, luminescence spectroscopy, elemental analysis and thermogravimetric analysis. The photoluminescence spectra of these complexes showed the typical europium (III) red emissions in solid state and chloroform solution, assigned to (D0Fj)-D-5-F-7 (j=0-4) transitions. The higher values of intensity parameter (2) indicated that the europium ion was in a highly polarizable ligand field in these complexes. Europium (III) complexes with the -diketone PFMP exhibited much better photoluminescence properties than complexes with the -diketone PFAP. Especially, the europium (III) complex of the -diketone PFMP with the auxiliary ligand 2,2-dipyridine displayed the longest lifetime value, the highest quantum yield and good CIE color coordinates matching the pure red color (x=0.67, y=0.33) in these complexes. In addition, the proposed energy transfer mechanisms and the thermal stability of these complexes were also investigated and analyzed.